HONOLULU — Hawaiʻi banana growers who are ranked number one nationally in banana production are being threatened by a perilous pathogen known as banana bunchy top disease . To help slow the spread of the disease, caused by the Banana bunchy top virus (BBTV), the Plant and Environmental Protection Sciences Department in the College of Tropical Agriculture and Human Resources (CTAHR) at UH Mānoa are producing and distributing tissue-cultured banana plants that are free of BBTV.

Plants infected early with BBTV do not bear fruit, and fruits of later infected plants are typically stunted, unattractive and not saleable. The disease is transmitted by a small soft bodied insect known as the banana aphid. BBTV was first reported in Hawaiʻi in 1989 and has since spread progressively.

"The spread of BBTV in Hawaiʻi is greatly influenced by the movement and use of infected plant material, thus, the use of field-grown banana suckers as replant material is risky," said Cerruti Hooks, a CTAHR entomologist. Cerruti shared that although the bananas may appear healthy, they may already be infected with BBTV. "Using known BBTV-free plants is the safest practice available today for replacing diseased banana plants."

In addition to BBTV, CTAHR nematologist Koon-Hui Wang discovered that many banana fields are infested with plant-parasitic nematodes. These nematode feed, multiply and migrate into the banana root system, where they impair water and nutrient uptake. This affects plant anchorage and toppling might occur under high infestations. Banana suckers collected from fields containing nematodes may already be infested with these organisms, but using tissue-cultured plantlets may also help prevent the unintentional spread of nematodes.

The University of Hawaiʻi at Mānoa Agricultural Diagnostic Service Center in coordination with the Hawaii Banana Industry Association are currently selling tissue-cultured banana plants. The plants were propagated from field collected banana plants that tested negative for BBTV and have not been genetically modified.